TRIASSIC FISHES FROM SPITZBERGEN 
19 
bergensis. The striation of the medial side appears on the whole to be coarser than 
that of the lateral side, but otherwise it is considerably more similar on both sides 
than was the case in A. spitzbergensis. It is possible to distinguish two types of striae, 
short and long, which show great differences in their arrangement. The long ones have 
their basal ends situated close to the basal margin of the crown and extend from there 
in a distal direction towards the primary longitudinal crista. They are connected directly 
with this only farthest out at the end of the crown. Otherwise they run together in 
groups, as has been described, and form a discontinuous secondary longitudinal crista 
both on the lateral and medial side of the primary longitudinal one. The short striae, 
which at the same time are fine, issue from the transversal crista, the primary longitu¬ 
dinal crista, the stumps of the secondary longitudinal cristae and the basal parts of 
several of the longer striae just described. Characteristically 
enough, they issue from these cristae and striae as a rule 
almost at right angles. On the transversal and primary longi¬ 
tudinal crista they are generally developed on both sides, 
on the stumps of the secondary longitudinal cristae and 
on the longer vertical striae, on the contrary, only on the 
side that is turned from the primary longitudinal crista. As they occur in great numbers 
they are very prominent and help essentially to give the general sculpture of the 
tooth a very characteristic appearance. The notch between crown and root on the 
medial side is small. The root is low and the basal surface is so situated that the 
axis of height through the crown meets it at right angles. Text fig. 5 shows a cross 
section through the tooth in question. 
The tooth P. 98 n (PI. 2, fig. 21) consists in its present state only of a fragment. 
It seems to agree well with P. 101 and does not need any special description. 
G 
Text fig. 5. 
Acrodus vermifonnis n. sp. 
Transverse section through the tooth 
P. ioi. ill. Medial side to the right. 
Remarks. — Acrodus vermifonnis appears in several respects to be closely related 
to A. spitzbergensis, but it is still too incompletely known to be separated from this 
species with certainty. As I have already pointed out, it is accordingly not improbable 
that among the teeth that I have provisionally grouped under the species name of 
A. spitzbergensis there may also be a few belonging to A. vermifonnis. 
The species name vermifonnis refers to the long and narrow shape of the crown, 
which together with the characteristic sculpture gives the teeth at a hasty glance a 
certain resemblance to the larva of an insect or to a worm. 
Geological occurrence and localities. — The tooth P. 98 n was found by 
Dr. J. Oppenheimer during the excursion of the Geological Congress to Spitzbergen in 
1910 and was presented , by him to the Palaeontological Institute of Upsala. As is 
shown by its number, it was found together with teeth P. 98 a—m of A. spitzbergensis 
and it is therefore probable that it comes from the same horizon and locality as these, 
i. e. the lower Saurian horizon at Mt Congress or Mt Tschermak. 
The tooth P. 101 was found at Mt Viking in the bone-bed 33 m above the fish 
horizon. 
